The fact that Azusa's doppelganger was playing her in the previous episode is revealed when Azusa says that she didn't go to the concert hall. However, only Conan and Amuro himself knows that the doppelganger was actually Vermouth in disguise. Conan thinks that since Vermouth bothered to investigate, the Black Organization must really be interested in the cipher left by Kōji Haneda seventeen years ago. Azusa also reveals that she saw a strange duo in front of Mōri Detective Agency talking something about "cleaning rags".

The strange couple was actually Heiji and Kazuha. They were talking about "rags to riches" which has a similar pronunciation. They came because the mayor of Yadori village, from Shimizu-ku in Shizuoka Prefecture, had found an important clue and sent Heiji a letter requesting help to unearth Tokugawa's buried treasure. Kogoro is nonchalant to the idea since the treasure will end up belonging to the government anyway. Scared of the dangers of treasure hunting, Ran initially refuses but consents when Kazuha and Heiji suggest that Shinichi might be invited there too.

The organizer and mayor Takekuma Densuke drive them to a run-down hotel. The hotel prospered at a time when tourists came to see the Kurogane Lake but since the incident when a member of the team unearthing Tokugawa's buried treasure died in an excavation accident. According to the legend, when Ieyasu was nearly captured in the war by Imagawa, an old couple hid in the Kurogane Forest. When the country finally stabilized, he gave the couple and their son a mountain of gold coins to thank them for their kindness. This is clearly mentioned in a nursery poem: "In the morning and evening sun, two thousand jars glitter with a thousand gold coins." The reporter, Hajime Tsurumi flirts with Kazuha and Ran facing Heiji's wrath. A dog appears which seems to like Tsurumi, making him to admit he doesn't like dogs.

Ran wanted to give an answer to Shinichi's confession in London and is sad because it seems the mayor didn't invite him. Meanwhile, Hattori is planning something on his own, probably a confession to Kazuha in a magnificent place and time.

Charles Abel was a foreigner who spoke broken Japanese. He was the one who got in the accident. When the team arrived, he was still alive, his body jammed between the rocks but he couldn't speak as his throat was destroyed. He was handed a piece of paper and pen to write. The team froze seeing what he had written "nue", a monster who has the head of a monkey, body of a tanuki (Japanese Raccoon Dog), legs of a tiger and tail of a snake. It is named after a bird which has the same eerie voice. The mayor actually wants to revitalize the town and gain publicity by making a video of the treasure hunt.

Accident (Past)

Location:

Yadori Village's cave

Victim:

Charles Abel

Age:

Unknown

Cause of death:

Cave-in accident

Nue appears in the middle of the fire.

When they go to sleep, Heiji notices fire in front of the hotel. When they rush to the site, the nue appears. It rips the warning sign and takes it away with its mouth. Heiji and Conan take the other way to avoid the fire. When they arrive, there are teeth marks in the signboard though the creature is nowhere to be seen. Conan finds blood spots on the ground. On going a bit further in the forest, they find Someji, the historian dead with long scratches on his back as though he was attacked by a wild beast.

Someone directed the mayor in a letter to invite the people to revitalize the village. The unknown sender also mentioned who should stay in which room. Ran and Kazuha exchange rooms and their room is taken by Tanzawa Michiki, the archaeologist. The reasons for inviting each of them were also mentioned. Tanzawa once examined the area of Shizuoka in the past. Until a few years ago, he was famous as a commentator in TV programs on ruins. However, he experienced a setback when some pottery he unearthed was suspected of being fake. Masuko Fumie is an author who is knowledgeable about Japanese monsters. She graduated from an art school.

The letters also suggested using the nue to revitalize the town if the buried treasure didn't work. Someji Yasukatsu, the murdered documentary reporter was a historian knowledgeable about Tokugawa's buried treasure. The letter simply suggested that Tsurumi Hajime is a fledgling reporter who travels across the country for monster stories. The members of the excavation team have all disappeared and even their names are unknown. Heiji was invited because the mayor had spent some amount of money for repairing the hotel so he was unable to invite Kogoro and also was unable to contact Shinichi.

While they are talking, fire engulfs the area and they hear the nue's scream. Tanzawa is heard screaming. He is found lying dead in his room with two sting marks on his chin, probably poisoned.

Murder

Location:

Yadori Village's villa

Victim:

Michiki Tanzawa

Age:

62 years old

Cause of death:

Poison

Suspects:

Densuke Takekuma, Fumie Masuko, and Hajime Tsurumi

Inspector Yokomizo Sango of Shizuoka Police appears. He seems suspicious of the situation initially but on seeing the evidence, he contacts his superiors to mobilize the self-defence force, a little too much of exaggeration on his part. The mayor mentions a drop of water falling on his cheek and the simultaneous sound of opening of a carbonated beverage. Fumie denies having to do anything with it and Tsurumi was too far away from the site of the incident.

The culprit used perspective shift to simulate the enlargement of the size of the nue. The culprit used a screen with a steep drawing of the windows in the hotel and dressed the dog as the nue. The tree in the line of sight of the observer and the darkness of the night combined with the smoke make the nue appear larger in size. The dog was trained to carry the sign on hearing the nue's cry, which was exchanged with the real sign with the giant teeth marks next to Someji's body to make it appear that the nue had killed him. The sound of the nue can be produced by rubbing a moist finger on the lip of a half-filled wine glass.

The Culprit was Fumie Masuko. Fumie admits she killed the two victims. Charles Abel was actually her husband. During the accident, Tanzawa and Someji had run away without trying to help Abel. Even after all these years, they had no repercussion of their deeds and shamelessly came to unearth the treasure that had once caused their coworker's death. Charles was actually trying to write "metal" ("tetsuno" in Japanese) as he had found a metallic hairpin. As a foreigner, he had never seen one before and after writing "metal", he was trying to show the team the paper and the hairpin to ask them what it was. But since he wrote with a permanent marker, the ink bled through producing "nue" instead. Heiji also reveals that Hajime is the son of Fumie and Charles. This is why, the dog recognizes him as his former owner. She invited Hajime to have him see her avenge his father. Similarly, according to one legend, the nue was actually the mother of Minamoto Yorimasa, who transformed into the beast so that her son could slay it.

Heiji tries to confess his feelings for Kazuha, but is interrupted by the Japan Air Self-Defense Force landing nearby on the orders of Yokomizo to capture the Nue and secure civilians. Surrounded by soldiers, Heiji decides not to confess. Some time later, the high-school student Momiji Ooka reads about the case on her smartphone and calls Heiji her future husband.

Because episode 872 adapted two files, episode 874 was adapted from only one file and five pages from file 961. In order for the episode to be 24 minutes long, the staff had to make some scenes longer or to create new scenes. In episode 874, when Heiji sews, he hurts himself with the needle. This wasn't in the manga.